In the field of the stocking knitting machines the needles are selected by means of the selection actuators arranged around the cylinder of the machine and intended to control the lower needles (or jacks) with radial deflection in order to control their passage by oscillation between an operating, deflected position and an inoperative, released position.
The lower needles have selection teeth at various levels and the selection actuators, which are electromagnetic or another type, comprise levers, which are able to intercept these selection teeth when the lower needles must be deflected and arranged in the operating position, and which are able not to interfere with these teeth when the lower needles must remain in the inoperative position.
In the operating position and as the cylinder rotates, the lower needles, forced by their lifting heel, follow the upward and downward courses defined by the stationary cams arranged around the cylinder. Therefore, the lower needles, rising, control the corresponding needles on the cylinder directly or indirectly by means of pushers and then return to a lowered position for a next selection.
According to the known embodiments, the selection teeth are integral with the lower needles and invariably follow all the upward and downward movements of the respective lower needles, and thus they also carry out vertical movements in relation to the selection actuators, which always remain stationary and at the same level.
Such a system does have some drawbacks which experts in the art know: for example, the difficulty in always obtaining and in making the level of the teeth coincide with that of the selection levers so that they are able to interact in a correct manner, the spaces necessary for the upward and downward movements of the lower needles which have a negative effect on the position of the selection actuators, as well as the number of the selection stations around the cylinder especially in multi-feed and multi-yarn knitting machines, etc.